This invention relates to novel olefin isomerization catalysts, and to methods for preparing and using the same. More particularly, this invention relates to an improved method for isomerizing olefins and diolefins in the presence of novel metal carbonyl catalysts formed by reacting certain ruthenium complexes with compounds which are readily decarbonylated in the presence of said complexes. This invention is also directed to the novel metal carbonyl catalysts themselves.
It is known that such compounds as RuCl.sub.2 (Ph.sub.3 P).sub.3 are catalysts for the isomerization of olefins. See, for example, Abley et al. Disc. of Farady Soc., 46, 31, 37 (1968). These reactions, however, are often characterized by very slow reaction rates, thus making such processes commercially impracticable.
There is also taught, in U.S. Pat. No. 3,530,198, a process for the preparation of olefins from carboxylic acids or their esters comprising contacting said acid or ester with a catalyst comprising a Group VIII metal complexed with an organometallic ligand of phosphorus, arsenic or antimony, to form olefins, carbon monoxide and water or alcohol. However, notwithstanding the presence of CO, olefin and organometallic catalyst in the reaction medium of this process, no increase in isomerization rate or selectivity is obtained when employing the acid or ester starting materials of this patented process in conjunction with the olefins of the present invention, as demonstrated by certain comparative examples set forth below. Moreover, as these examples will also demonstrate, none of the carbonyl complex comprising the novel catalyst of this invention is formed when this prior art method is employed.